The present invention relates to a composite article of manufacture, and particularly a composite baseball bat suitable for replacing aluminum bats.
Various articles of manufacture are fabricated out of wood. Exemplary articles include boat hulls, pylons, bridges, beams, trusses, decking, masts, columns, and sports equipment including bats and rackets. There are, however, several limitations on the use of wood. Wood tends to crack, warp and rot when exposed to the elements requiring repair or replacement. An alternative has been to use wood laminates wherein multiple wood segments are bonded together such as glue-laminate members. However, such laminates often do not have the same physical and aesthetic characteristics as articles formed from a solid piece of wood. Certain types of wood are becoming short in supply such as mahogany for furniture and white ash for baseball bats. Also articles like baseball bats have performance and aesthetic characteristics that are difficult to simulate unless a solid piece of wood is used.
Most leagues other than Major League Baseball exclusively use metal (aluminum) bats. Historically, this was primarily as a cost savings measure in that wooden bats break easily and are expensive to replace. Today, most leagues other than Major League Baseball had converted to aluminum bats because of the savings primarily in the replacement of broken bats. Most metal bats are made principally of aluminum which can be coated to look like wood but which perform differently than wood bats and are known to create a metallic pinging sound rather than the traditional xe2x80x9ccrack of the batxe2x80x9d heard when a wood bat impacts a ball. Moreover, metal bats are considered aesthetically unpleasing by some more traditionally oriented individuals who are used to the typical appearance, performance and sound made by the impact of a wood bat.
Metal bats are distinctly advantageous in that, while more expensive to manufacture, they do not break and can therefore be used repeatedly with consequent cost savings. Metal bats are however, coming under increased scrutiny due to the speed of the ball off of the bat. By coming off a metal bat faster, pitchers and other players and spectators are at increased risk of being hurt because of reduced reaction time. Although metal bats have a larger xe2x80x9csweet spotxe2x80x9d and generally perform better than wood and have been found acceptable at levels from Little League up through college baseball, metal bats have not yet been approved for Major League or minor league baseball use, partly because the ball speed off the metal bat is faster and, secondly, because of the undesirable pinging sound normally associated with metal bats.
Many leagues are however considering banning metal bats primarily because of the safety issues, and secondarily because of performance issues. As outlined in the USA Today, Dec. 15, 1998 issue, Section C, page 3, the NCAA was considering banning metal bats for the 1999 season because of performance, namely the NCAA wanted baseball xe2x80x9ccloser to its traditional formxe2x80x9d and cites xe2x80x9crunaway bat performancexe2x80x9d as a consideration. Additionally, the NCAA expressed a concern that the high performance metal bats are so lively that players and spectators, particularly pitchers are unable to react quick enough.
The National Federation of High Schools (NFHS) has adopted new rules with respect to make aluminum bats more akin to wooden bat performance. The rule would require non-wood bats have 2⅝ inch maximum barrel diameter, a minus 3 unit maximum differential based on length to weight ratio, and a minimum moment of inertia (MOI) of 9000 0 z-in2 measured at the 6 inch point from the knob. The NFHS believes that such a weight and MOI would cause the effort required to swing such a non-wood bat to replicate the effort required to swing a wooden bat. Additionally, a maximum exit ball speed is being considered. See, NFHS Press Release of Aug. 3, 1999.
Various attempts have been made to either provide composite baseball bats using wood or to provide composite baseball bats simulating wood more than conventional aluminum bats. For example, U.S. Pat. No. 4,032,143 to Mueller et al. proposes an aluminum core surrounded by a form plastic body. Such a bat is said to be a lighter and less expensive bat suited for younger players (See, Column 1, lines 41-42).
U.S. Pat. No. 4,572,508 to Young proposes a baseball bat formed by a plurality of laminations held together by dovetail-shaped grooves and ridges. Layers of carbon fibers impregnated with a thermosetting resin are sandwiched between the wooden laminations to provide strength and shock absorbing characteristics.
U.S. Pat. No. 4,848,745 to Bohannon et al. proposes a cured foam core bat or bowling pin having circumferentially wound fibers sandwiched between two layers of fibers aligned with the longitudinal axis of the bat.
U.S. Pat. Nos. 5,114,144, 5,460,369 and 5,460,369 all to Baum disclose wood composite baseball bats having an aluminum core overwrapped with a composite reinforcing layer and covered with an outer layer of resin coated wood veneer. These bats are complex and expensive to manufacture, and uses an actual wood exterior to achieve the performance and appearance of a wood bat.
U.S. Pat. No. 5,301,940 to Seki et al. proposes a method of molding a baseball bat by winding reinforcing fibers around a core, placing this in a mold and injecting a resin which is a crosslinked polyaminoamide resin, a crosslinked epoxy modified polyamidoamide resin or a polyesteramide resin into the mold and curing the bat.
U.S. Pat. No. 5,395,108 to Sauders et al. proposes a synthetic wood composite bat comprising a shell of fiber reinforced resin material, a fiber tube inside the shell and a rigid cured polyurethane form filling the shell and penetrating the inner portion of the tube.
U.S. Pat. No. 5,409,214 to Cook proposes a baseball bat having a hollow metal handle portion and a solid wood barrel portion positioned in the handle portion.
U.S. Pat. No. 5,800,293 to MacKay, Jr. proposes a laminated wood bat constructed of a plurality of thin wood veneer bundled together throughout its facing surfaces.
None of these bats, however, sufficiently match the characteristics of existing wooden baseball bats. Therefore, it can be appreciated that there is still a need for an improved composite baseball bat structure.
It is therefore an object of the invention to provide a composite baseball bat substantially mimicking the appearance, performance and sound of a conventional all-wood bat.
It is another object of the invention to provide a composite baseball bat that replicates the effort required to swing an all-wood bat and results in substantially the same maximum exit ball speed and minimum moment of inertia as that of an all-wood bat.
It is yet another object of the invention to provide a composite baseball bat that is more durable than an all-wood bat.
To this end, the present invention provides a composite baseball bat. The baseball bat generally includes a core having a barrel portion and a handle portion wherein the core is wound at various angles with continuous fibers. The fibers are impregnated with a resin such as an epoxy resin.
In one embodiment, the baseball bat comprises a core having a barrel portion, handle portion and a longitudinal axis extending through core barrel and handle portions, the handle portion being narrower than the barrel portion; continuous first fibers wound around the core barrel portion at an angle of about 0xc2x0 to 90xc2x0 relative to a first plane normal to the longitudinal axis to provide at least one layer of first fibers around the core barrel portion; continuous second fibers wound around the core handle portion at an angle of about 35xc2x0 to 55xc2x0 relative to the first plane normal to the longitudinal axis to provide at least one layer of second fibers around the core handle portion; and a resin impregnated on the first and second fibers.
In another embodiment, the baseball comprises a core having a top barrel portion, a throat portion, a transition portion between the barrel and throat portions, a handle portion adjacent the throat portion and a bottom knob portion, and a longitudinal axis extending through the barrel, throat, transition, handle and knob portions, the handle portion being narrower than the barrel portion; continuous first fibers wound around the core barrel portion at an angle of about 35xc2x0 to 55xc2x0 relative to a first plane normal to the longitudinal axis to provide at least one layer of first fibers around the core barrel portion; continuous second fibers wound around the core throat portion at an angle of about 15xc2x0 to 35xc2x0 relative to the first plane normal to the longitudinal axis to provide at least one layer of second fibers around the core throat portion; continuous third fibers wound around the core transition portion between the barrel and throat portions at an angle of about 25xc2x0 to 45xc2x0 relative to the first plane normal to the longitudinal axis to provide at least one layer of third fibers around the core transition portion; continuous fourth fibers wound around the core handle portion at an angle of about 5xc2x0 to 25xc2x0 relative to the first plane normal to the longitudinal axis to provide at least one layer of fourth fibers around the core handle portion; continuous fifth fibers wound around the core knob portion at an angle of about 35xc2x0 to 55xc2x0 relative to the first plane normal to the longitudinal axis to provide at least one layer of fifth fibers around the knob portion; and a resin impregnated on the fibers. A method of making such a bat is also provided.